Obtainment And Characterization Of Transgenic Brassica Napus With GmDof4or GmDof4Genes

Rapeseed is one of most important oil crops in the world, with the feature of adaptable, versatile, high economic value. At present, China’s rapeseed production is also difficult to meet domestic consumer demand. With the development of modern biotechnological strategies, genetic engineering methods have been widely used in the breeding of high yielding and disease-resistant oilseed rape varieties. Two genes, GmDof4and GmDofll, cloned from Glycine max, are the Dof-like transcription factors involving in the regulation of the lipid content in soybean seeds. Previous studies suggested that the content of total fatty acid and lipid in the GmDof4and GmDofll transgenic Arabidopsis thaliana plants seeds were increased. Besides, expressions of some genes whose products are associated with the responses to stress were up-regulated in transgenic plants. In this study, Brassica napus was transformed by using Agrobacterium tumefaciens harbouring the plasmids containing GmDof4and GmDofll genes, respectively. At last, we obtained the positive regeneration plants.Based on the original method of the laboratory, we also optimized genetic transformation system of rapeseed hypocotyls. The main results were as follows:(1) Compared with the normal ones, we found that hypocotyl cuttings from yellow rape seedlings had no significant changes of the growth status in the screening stage, but etiolated hypocotyls were difficult to turn green when growing in the selective medium with light. This is beneficial to remove unwanted hypocotyls without exogenous gene during the subculture process.(2) With the treatment of pre-training process for3days before infected by Agrobacterium, we found that the viability of hypocotyls could be improved.(3) Different from co-cultured in the solid B1medium, the hypocotyls were co-cultured in10ml liquid B1medium mixed with20μl Agrobacterium culture in dark for3days. We found that this method was more conducive to callus formation and growth.(4) Before transferred to the selective medium, the hypocotyls were cultured on the recovery medium for a week. This method could reduce the decline of viability caused by the manufacturing of wound and Agrobacterium infection. It was conducive to screen positive callus.